Task 1: Literature review and data gathering

A comprehensive review of the existing literatures on former research according to this topic is conducted.

Task 2: Experimental investigation

This part focuses on gaining a better understanding on the gas migration phenomenon and coupled THM process that may lead to the formation of cracks under repositiry conditions. The effect of interfaces between dissimilar materials will be investigated as well.

Task 3: Constitutive modelling

Already published data and the results to be gethered in Task 2 will be used to develop and validate new constitutive laws. CODE_BRIGHT incorporates a conprehensive libruary on constitutives for models for the hydraulic, thermal, and mechanical problems, which will be upgraded to incorporate the specific physics associated with the presence of discontinues in geomaterials.

Task 4: Numerical modelling

The activities associated with the numerical modeling will be centered on the extention of a fully coupled THMC finite element 3D program CODE_BRIGHT to deal with discontinuities and interfaces in geological materials. This code is based on a multiphase/multi-species mathematical formulation that consists of three main set of equations: balance equations, constitutive equations and equilibrium restrictions.

Task 5: Application cases

This task will focus on the application of the proposed numerical approach to model typical design concepts for nuclear waste disposal. Four types of studies will be conducted:

• Selected experiments from Task 2
• Case studies associated with actual medium/large scale tests available in the literature
• Generic synthetic cases
• Sensitivity studies and parametric analysis